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Mycoplasmalike Bodies Associated with Elm Phloem Necrosis. Charles L. Wilson, Plant Pathologist, Plant Science Division, ARS, USDA, Delaware, Ohio 43015; Carl E. Seliskar(2), and Charles R. Krause(3). (2)Principal Plant Pathologist, FS, USDA, Northeastern Forest Experiment Station, Delaware, Ohio 43015; (3)Technician, Plant Science Division, ARS, USDA, Delaware, Ohio 43015. Phytopathology 62:140-143. Accepted for publication 12 August 1971. DOI: 10.1094/Phyto-62-140.

Mycoplasmalike bodies were found associated with phloem cells in the roots and stems of American elms (Ulmus americana) infected by the elm phloem necrosis agent, but not in healthy elms. These bodies were limited by tripartite membranes (about 8 nm in width) and varied in diameter from 200 to 1,000 nm. They exhibited pleomorphic forms plus internal morphology typical of mycoplasmas. No virus particles were seen in phloem necrosis-diseased cells; however, numerous phloem elements were filled with plant protein.